package ch2;

import java.util.Scanner;

/**
 * @author oldliu
 * @since 1.0
 */
public class Circle {
    public static void main(String[] args) {
        Scanner input=new Scanner(System.in);
        System.out.println("input radius:");
        double r=input.nextInt();
        int area= (int) (r*r*3.14159);
        System.out.println("面积是："+area);
    }
}
